Medical science has long sought ways to minimize the dangers and trauma inherent in invasive surgical procedures. To this end, surgical techniques and instruments have been developed which, among other things, reduce the size and number of the incisions required to perform various surgical procedures. These techniques and instruments have been remarkably successful. Procedures that only a few years ago would require multiple incisions several inches in length are today being performed with just a few small incisions.
During minimally invasive surgeries, surgical instruments such as trocars, cannulas, and optical medical devices, including endoscopes, cystoscopes, arthroscopes, laparoscopes, etc., are inserted through small incisions or portals in a patient's body or body cavity and manipulated to perform surgical procedures within the patient.
Minimally invasive surgical procedures such as arthroscopy are safer than open surgery and result in quicker patient recovery, shorter hospital stays, and lower health care costs. Accordingly, minimizing invasiveness continues to be of importance, and there is a continuing need for devices and methods that achieve this objective.
One significant barrier to further minimizing the invasiveness of surgery is the necessity of many surgical instruments to have fluid channels. These channels effectively add to the outer diameter of the instruments. For example, known endoscopic instruments provide inflow/outflow through an assembly of concentric sheaths that define channels for inflow and outflow of fluids to and from the operative or surgical site. The fluid may be an irrigating solution that helps maintain a clear view of the site for the physician. Certain known irrigating systems provide simultaneous and continuous inflow and outflow. These systems are known as “continuous flow” systems.
The known inflow and outflow endoscope systems introduce an irrigating fluid into the surgical site. For this purpose, the endoscope has an inflow channel defined by the inner surface of the sheath. The fluid passes through the channel and exits the distal end of the sheath to irrigate the operative site. Fluid at the surgical site may be withdrawn through an outflow channel defined by the outer surface of the inner sheath and the inner surface of a surrounding outer sheath. The outflow channel originates at the distal end (front end) of the instrument and transports fluid to an exit point at the proximal end of the outer sheath. The diameter of these systems requires larger surgical portals.
Another barrier to minimally invasive surgery is fluid management within the surgical site. During arthroscopy, fluid is pumped into the joint under pressure to maintain distention in the joint for visualization and hemostasis. A computerized pump that precisely monitors the flow rate and intra-articular pressure usually accomplishes this. Poor fluid management, however, can lead to complications. If pressure is set too low, excessive bleeding and poor visualization could occur. If the pressure is set too high and for too long, significant swelling in the surrounding tissue can occur. During arthroscopic knee surgery, excessively high pressure could result in compartment syndrome of the leg.
In arthroscopic surgery, as well as other surgical procedures, there remains a significant need for improved techniques that reduce the size of the portals while providing substantially continuous and properly managed fluid inflow and outflow. The Applicant's improved inflow/outflow sheath reduces the diameter of the continuous flow system while properly managing surgical site fluid inflow and outflow.